I disagree. The internet has increased the reach of individuals by many orders of magnitude: we (humanity) are experiencing the consequences of something we're not equipped for, but that isn't the fault of Twitter or Facebook, it's a consequence of the internet connecting us all.

What, specifically, has Twitter done, that has been a negative influence on the culture? If you look at, say, Donald Trump, he was across the internet being divisive in every venue he could get his hands on, from Facebook to Reddit... and outside of the internet too, on Fox News and the like.

If we went back 2 decades and put all of humanity on a bbs or newsgroup instead, you'd have the same outcome.